The present invention relates generally to techniques for identifying circuits within electrical devices.
Electrical devices commonly consist of one or more circuit boards mounted inside some manner of mechanical case. These circuit boards further commonly have a number of circuits mounted on each board. Often there is a need to identify one or more of the circuits mounted on each board within the electrical device. For example, in the instance where the device is to be loaded with new software and the proper version of software is dependent on the identities of the circuits within the electrical device, it would be necessary to determine the identities of the circuits within the electrical device. A manual inspection of the electrical device may, of course, be conducted. Such a manual inspection, however, will likely require some lengthy disassembly. Furthermore, even after disassembly, the identity of the individual circuits on the circuit boards may not be so readily apparent as to make them easily identifiable by visual inspection. Thus, it would be advantageous to have the capability to electrically communicate the identity of one or more circuits located within an electrical device to an external entity.
Electrical communication of the identity of circuits within an electrical device has conventionally been performed using two-way communication buses. With this conventional technique, a device outputs, on the two-way bus, the identity of a circuit within the device in response to requests received over the two-way bus. Conventionally, two-way communication buses are implemented in CMOS circuitry using standardized cells that consume small quantities of energy. When the electrical device uses analog bipolar circuitry, however, use of a two-way bus is impractical because of its complexity and high power consumption. Therefore, electrical devices with analog bipolar circuitry usually only have the capability for one-way communication and thus can only receive data without having the capability of transmitting data. Communicating the identity or identities of circuits within an electrical device therefore is problematic when the electrical device uses primarily analog bipolar circuits.
Thus, it is an object of the exemplary embodiments of the present invention to provide a technique for identifying a circuit within an electrical device.
It should be emphasized that the terms xe2x80x9ccomprisesxe2x80x9d and xe2x80x9ccomprisingxe2x80x9d, when used in this specification, are taken to specify the presence of stated features, integers, steps or components; but the use of these terms does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.
According to one exemplary embodiment of the invention a circuit within an electrical device is identified. In some embodiments, this is accomplished by: measuring a first current drawn by the circuit; and, for a number of times, n, successively controlling at least a portion of the circuit so as to affect the current drawn by the circuit, and for each of the n times, measuring the affected current drawn by the circuit, wherein n is a number greater than or equal to 1. The identity of the circuit is then determined using n values corresponding to the difference between each of the n affected currents and the first current.
In some embodiments, it may be sufficient to let n be equal to 1, and still be able to identify which of a number of possible circuits the particular circuit of interest is.
According to a further exemplary embodiment of the invention a system for identifying a circuit within an electrical device is provided. This exemplary embodiment comprises: logic that sends a control signal to the circuit over a first circuit path; logic that outputs from said circuit over a second circuit path one or more signals in response to said control signal; and logic that identifies said circuit based on said one or more signals.
According to an additional exemplary embodiment of the invention a method for identifying a circuit within an electrical device is provided. This exemplary embodiment comprises: sending a control signal to the circuit over a first circuit path; outputting from the circuit one or more signals over a second circuit path in response to said control signal; and identifying the circuit based on the one or more signals.